In electronic equipment used in e.g. FA (factory automation), telecommunication, and OA (office automation), signal transmission is often performed between different power supply systems at input and output.
Direct coupling between different power supply systems is prone to various problems in operation and safety.
Optical transmission modules for free-space transmission are used for electronic equipment having a short transmission distance. Optical transmission modules for fiber-optical transmission are used for electronic equipment having a long transmission distance. Thus, it is necessary to prepare many kinds of products of optical transmission modules.